How many years do rats live for?

Rats' lifespans vary depending on the species. For instance, brown rats (Rattus norvegicus) have an average lifespan of 1-2 years in the wild, while black rats (Rattus rattus) can live up to 3 years. In controlled laboratory settings, some rat species can live for up to 4-5 years. However, in both wild and domestic environments, rats rarely reach their full lifespan due to various factors such as predation, disease, and competition.